| | Mobridge, SD | Prince Frederick, MD | United States |
| Population | 3,215 | 2,350 | 329,725,481 |
| Female Population | 52.8% | 58.6% | 50.5% |
| Male Population | 47.3% | 41.4% | 49.5% |
| Median Age | 41.4 | 43.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,465 | 2,601 | 309,327,143 |
| Population - 2000 | 3,574 | 1,432 | 285,036,114 |
| Population - 1990 | 3,768 | 1,885 | 251,960,433 |
| Pop. 2000 to Now | -5.6% | 120.0% | 15.6% |
| Pop. 1990 to Now | -10.5% | 67.2% | 30.8% |
| space4 | | | |
| Population Density | 1,664.1 | 641.7 | 93.4 |
| Land Area | 1.9 | 3.7 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Mobridge, SD | Prince Frederick, MD | United States |
| Age 0 to 4 | 6.3% | 3.8% | 5.9% |
| Age 5 to 9 | 5.4% | 4.4% | 6.1% |
| Age 10 to 14 | 8.5% | 3.6% | 6.6% |
| Age 15 to 17 | 2.2% | 5.0% | 3.9% |
| Age 18 to 20 | 2.8% | 5.5% | 4.0% |
| Age 21 to 24 | 3.7% | 4.2% | 5.2% |
| Age 25 to 34 | 11.0% | 11.3% | 13.8% |
| Age 35 to 44 | 14.5% | 13.4% | 12.9% |
| Age 45 to 54 | 6.9% | 10.2% | 12.6% |
| Age 55 to 59 | 7.4% | 7.9% | 6.7% |
| Age 60 to 64 | 9.2% | 7.1% | 6.3% |
| Age 65 to 74 | 11.0% | 7.0% | 9.6% |
| Age 75 to 84 | 8.7% | 11.1% | 4.5% |
| Age 85 and over | 2.2% | 5.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Mobridge, SD | Prince Frederick, MD | United States |
| White | 69.0% | 55.7% | 59.4% |
| Black | 6.1% | 24.9% | 12.2% |
| Asian | 0.3% | 9.0% | 5.6% |
| Native American | 18.6% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 4.4% | 3.5% | 3.2% |
| Hispanic | 1.5% | 6.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Mobridge, SD | Prince Frederick, MD | United States |
| Married Population | 46.2% | 38.2% | 49.8% |
| Currently Married | 42.5% | 36.0% | 48.0% |
| Married but Separated | 3.7% | 2.2% | 1.8% |
| Single Population | 53.8% | 61.8% | 50.2% |
| Never Married | 29.9% | 34.5% | 33.8% |
| Divorced | 15.3% | 12.8% | 10.8% |
| Widowed | 8.6% | 14.5% | 5.6% |
| space5 | | | |
| Household Size | 2.06 | 2.06 | 2.60 |
| Households | 1,462 | 1,059 | 124,010,992 |
| Family Households | 817 | 524 | 80,755,759 |
| Married couple, w/children | 21.1% | 38.9% | 30.5% |
| Married couple, no children | 43.7% | 32.1% | 42.9% |
| Non Family Households | 645 | 535 | 43,255,233 |
| Single householder, w/children | 18.0% | 17.0% | 15.8% |
| Single householder, no children | 17.3% | 12.0% | 10.8% |